This invention relates to radial fans used to move or draw air through a heat exchanger, and in particular to the blade configuration of such fans.
Radial fan blades are usually configured to produce an optimum flow of air through or over a heat exchanger at a particular speed of rotation of the fan. It is difficult to significantly increase the volumetric flow of air for a given radial fan without substantially redesigning the radial fan blades. This can include either changing the shape or thickness of the fan blade so as to increase the rigidity of the fan blades to handle the increased flow of air. It would be preferable to increase the rigidity of the fan blades without necessarily going through a substantial redesign of the fan blades.
The invention features a fan blade configuration for a radial fan that includes support structure for the cantilevered portion of each blade. The support structure increases the rigidity of the cantilevered portion of said blade so as to allow the radial fan to operate at higher speeds. This support structure is preferably affixed to an upper ring of the radial fan and extends outwardly therefrom in support of the cantilevered portion of the blade. The support structure preferably extends along the cantilevered portion of the blade for a predefined distance. The distance is preferably expressed relative to a distance to a point at which the leading edge of the blade terminates. The predefined distance is also a function of the downward inclination of the support structure extending along the cantilevered portion.